73-87 Chevy & GMC C10 Squarebody Rear Frame C-Notch Kit (Bolt-On)

73-87 Frame C-Notch Kit - #130-4000

The GSI Rear Frame C-Notch Kit is the definitive solution for 1973-1987 Chevy & GMC trucks that require increased axle clearance. When lowering a Squarebody more than 4 inches, the factory frame rail becomes a bottleneck for suspension travel. Our C-notch provides the necessary "relief" to prevent harsh axle-to-frame contact, ensuring a smooth ride even on aggressive drops. Engineered for builders who want a professional-grade foundation without the complexity of a full back-half.

The GSI Advantage

• Bolt-In Simplicity: Unlike traditional "weld-in only" notches that require extensive fabrication and frame stripping, our kit is designed as a precision bolt-in unit. This significantly reduces installation time and allows for a cleaner, more approachable DIY process.

• Structural Integrity: While designed for a bolt-in application, the high-strength steel construction allows for optional welding for builders who prefer a fully integrated, permanent bond for high-horsepower or heavy-duty air ride builds.

• Preserved Suspension Geometry: By allowing for proper upward travel, this kit prevents the "bottoming out" effect common in lowered trucks. This protects your shocks, bushings, and rear-end components from impact damage.

• Complete Installation Solution: We include a custom metal installation template to take the guesswork out of cutting your frame. This ensures your notches are perfectly centered and square every time.

Design & Construction

• Weight: 26 lbs (Total Kit) / 13 lbs (Per Notch)

• Dimensions: 17" x 3.5" x 5" (Per Notch)

• High-Strength Steel: Laser-cut and formed for a precise fit over factory frame rails.

• Grade 8 Hardware: Includes (26) 1/2"-13 heavy-duty bolts and Nylock nuts for a secure, vibration-resistant connection.

• Application-Specific: Contoured specifically for the 1973-1987 GM C10/K10 frame profile.

Measurement & Fitment Guide

This kit is purpose-built for the GM Square Body platform (1973-1987). While it is a "universal" fit for this specific year range of Chevy and GMC trucks, please verify your suspension setup before installation.

When to use this kit:

• Rear Drops: Mandatory for rear drops of 4" or greater.

• Air Ride Systems: Highly recommended for all air suspension applications to allow the truck to "lay frame" or achieve maximum drop.

• Static Drops: Ideal for flip-kit setups or lowered leaf spring configurations that experience frequent bottoming out.

Vehicle Applications

• 1973-1987 Chevy C10 (2WD)

• 1973-1987 GMC C15 (2WD)

What’s Included

• (2) Rear Frame C-Notches

• (1) Metal Installation Template

• (26) 1/2"-13 x 1.25" Bolts

• (26) 1/2"-13 Nylock Nuts

• (54) 1/2" Washers

Questions? Contact Us

(480) 940 1806 – Local
1 (877) 951-1890 – Toll Free

At GSI Machine & Fabrication, we offer a one-year warranty on all manufactured parts, covering defects upon inspection. However, we are not liable for personal or property damages resulting from misuse of our products. Note that warranties for non-manufactured parts, such as shocks or ball joints, must be handled directly with the part’s manufacturer.

Orders may be canceled before shipment, except for special-order and custom items, such as chassis products and air ride suspension. Refunds for eligible returned items will exclude shipping costs and may incur additional fees. For cancellations or issues with orders, contact our customer support at 1 (877) 951-1890 or sales@gsimfab.com.

Customers are responsible for all customs fees, duties, and taxes on international orders. Once your package is shipped, we are not liable for damage, theft, or loss during transit. Please inspect your delivery promptly and report any issues within 48 hours. For international shipments, local policies may cause delays, and additional documentation may be required. Always ensure shipping details are accurate to avoid additional costs.